| 摘要 |
The bleeder comprises a hydraulically remotely controlled bleed valve and means for guaranteeing that during bleeding, the gas is exhausted away from the well head zone. The bleed valve is advantageously situated at the top end of the pressure lock and comprises a valve body defining a main channel of sufficient cross-section to pass a wireline tool, a gas exhaust lateral orifice for being put selectively into communication with a first transverse channel opening out into the main channel by means of a closure member constituted by a valve seat and a valve member formed at one end of a piston , a second transverse channel putting the main channel into communication with a rear face of the piston , said rear face having a greater section than its valve-forming front face, and a lateral hydraulic fluid receiving control orifice connected to a hydraulic remote control flexible hydraulic pipe and opening out into a bore defining an annular space around a portion of the piston , said bore being of smaller section than the rear face of the piston in contact with the gas present in said second transverse channel . |
